1. Field
The present disclosure relates to electrophotographic photoreceptors and electrophotographic imaging apparatuses.
2. Description of the Related Art
Recently, organic photoreceptors using organic materials have come into widespread use as electrophotographic photoreceptors due to lower manufacturing costs thereof than inorganic photoreceptors such as amorphous silicon.
Various electric and mechanical stresses caused by charging, toner attaching, transferring, and cleaning processes are applied to a surface layer of an organic photoreceptor. Since these stresses applied to the surface layer of the organic photoreceptor may degrade image quality, there is a need to develop a photoreceptor having high durability.
In order to remove toner or paper dust attached to the surface of the organic photoreceptor and hydrophilic materials generated during a charging process, cleaning methods by bringing a urethane-based rubber cleaning blade into contact with the surface of the photoreceptor have been generally used.
However, when the surface of the photoreceptor has high frictional resistance, the cleaning blade may be inverted or a squeal noise may be generated from the cleaning blade. In addition, as the cleaning blade is slowly damaged, and toner leaks from the cleaning blade, image defects may be caused due to poor cleaning performance. Thus, by improving cleaning performance by inhibiting frictional resistance of the surface of the photoreceptor, images may be stably acquired for a long time.
Meanwhile, in view of abrasion resistance, mechanical properties of a photoreceptor may be improved by forming a protective layer on the surface of the photoreceptor and introducing a curable resin or a filler into the protective layer. For example, a protective layer including a curable resin and formed on the surface of the photoreceptor, a protective layer including a filler, and an attempt made to further improve the mechanical strength of a protective layer by surface-treating a filler and allowing the surface-treated filler to form a cross-linking structure with adjacent resin have been disclosed.
However, sufficient cleaning performance cannot be obtained merely by increasing mechanical strength. It is difficult to obtain a photoreceptor having all of abrasion resistance, cleaning performance, and scratch resistance. Thus, attempts have been made to reduce frictional resistance of the surface of the photoreceptor by improving lubricity of the surface of the photoreceptor by adding fluorine resin particles to a protective layer.
Protective layers to which fluorine resin particles are added have been disclosed. However, even when using such protective layers, it is difficult to maintain a high cleaning performance of the protective layers for a long time.
In addition, an attempt has been made to add a lubricant such as silicone oil to a protective layer and a protective layer to which silicone oil is added has been disclosed. However, the lubricant often forms segregation on the surface of the photoreceptor, and thereby, effects thereof may vanish as the surface of the photoreceptor wears away.
A protective layer to which silicone oil having a functional group is added in order to inhibit surface segregation of the lubricant has been disclosed. However, it is difficult to inhibit surface segregation even when the silicone oil having a structure illustrated in this patent document is used, and thus, such a silicone oil is insufficient to maintain a high cleaning performance for a long time.